Cell growth + division lecture 6

Question 1

Environmental requirements for mammalian cell proliferation

Answer 1

• Yeast + bacteria = controlled by nutritional status

- Mammalian cells need nutrients, macromolecular nutrients + growth factors

Question 2

Quiescence

Answer 2

• W/o serum, cells withdraw → quiescence
• Comb of factors
• W/o serum arrest btw M + S in G0
• Re-enter into Go

Question 3

Restriction point

Answer 3

• GF act before restriction point to activate CDKs

- When pass x need GF anymore

Question 4

CDKs

Answer 4

• To progress through G1, cells require activation of G1 Cdks
• Later in G1, cyclinE/CDK2 are activated
• In S = cyclin A + B

Question 5

Tyr kinase receptor

Answer 5

• Has single TM pass domain

- Insulin/insulin-like = exception

Question 6

Experiment

Is Tyr kinase required for mitogenic response

Answer 6

• Transfect w/ ‘novel’ RTK
• Treat cell w/ receptor
• Does activate ds signal
• See what part of receptor needs e.g. mutate kinase

Question 7

RTK activation

Answer 7

• Activation by dimerisation → brings together IC region of tyrosine kinase → phosph each other
• Associate w/ SH2
• Several effects (change localisation, phosphorylation, allosteric activation)

Question 8

Cooperativity of signalling pathways

Answer 8

• Mutate individual Tyr so x phosph

- No single pathway is responsible

Question 9

G-protein linked receptor

Answer 9

• E.g. endothelin
• 7TN, activates G protein
• GDP → GTP
• a subunits varied
• By activate P13K, PLC-y

Question 10

Cytokine receptor

Answer 10

• Assoc. w/ non-RTK like JAK

- Binding of receptor to cytokine stab. dimeric form

Question 11

Ser/Thr kinase receptor

Answer 11

• TGFB
• Ser/Thr kinase assoc w/ IC domain
• Heterodimer (TGFB)

Question 12

Notch receptor

Answer 12

• Long EC domain

- 2 proteolytic events